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[PATCH] cpusets: oom_kill tweaks
[linux-2.6/kvm.git] / include / asm-ppc / uaccess.h
blob63f56224da8ca3b69361b9f6801a81a80d12c6e3
1 #ifdef __KERNEL__
2 #ifndef _PPC_UACCESS_H
3 #define _PPC_UACCESS_H
4
5 #ifndef __ASSEMBLY__
6 #include <linux/sched.h>
7 #include <linux/errno.h>
8 #include <asm/processor.h>
9
10 #define VERIFY_READ 0
11 #define VERIFY_WRITE 1
12
13 /*
14 * The fs value determines whether argument validity checking should be
15 * performed or not. If get_fs() == USER_DS, checking is performed, with
16 * get_fs() == KERNEL_DS, checking is bypassed.
17 *
18 * For historical reasons, these macros are grossly misnamed.
19 *
20 * The fs/ds values are now the highest legal address in the "segment".
21 * This simplifies the checking in the routines below.
22 */
23
24 #define KERNEL_DS ((mm_segment_t) { ~0UL })
25 #define USER_DS ((mm_segment_t) { TASK_SIZE - 1 })
26
27 #define get_ds() (KERNEL_DS)
28 #define get_fs() (current->thread.fs)
29 #define set_fs(val) (current->thread.fs = (val))
30
31 #define segment_eq(a,b) ((a).seg == (b).seg)
32
33 #define __access_ok(addr,size) \
34 ((addr) <= current->thread.fs.seg \
35 && ((size) == 0 || (size) - 1 <= current->thread.fs.seg - (addr)))
36
37 #define access_ok(type, addr, size) \
38 (__chk_user_ptr(addr),__access_ok((unsigned long)(addr),(size)))
39
40 /*
41 * The exception table consists of pairs of addresses: the first is the
42 * address of an instruction that is allowed to fault, and the second is
43 * the address at which the program should continue. No registers are
44 * modified, so it is entirely up to the continuation code to figure out
45 * what to do.
46 *
47 * All the routines below use bits of fixup code that are out of line
48 * with the main instruction path. This means when everything is well,
49 * we don't even have to jump over them. Further, they do not intrude
50 * on our cache or tlb entries.
51 */
52
53 struct exception_table_entry
54 {
55 unsigned long insn, fixup;
56 };
57
58 /*
59 * These are the main single-value transfer routines. They automatically
60 * use the right size if we just have the right pointer type.
61 *
62 * This gets kind of ugly. We want to return _two_ values in "get_user()"
63 * and yet we don't want to do any pointers, because that is too much
64 * of a performance impact. Thus we have a few rather ugly macros here,
65 * and hide all the ugliness from the user.
66 *
67 * The "__xxx" versions of the user access functions are versions that
68 * do not verify the address space, that must have been done previously
69 * with a separate "access_ok()" call (this is used when we do multiple
70 * accesses to the same area of user memory).
71 *
72 * As we use the same address space for kernel and user data on the
73 * PowerPC, we can just do these as direct assignments. (Of course, the
74 * exception handling means that it's no longer "just"...)
75 *
76 * The "user64" versions of the user access functions are versions that
77 * allow access of 64-bit data. The "get_user" functions do not
78 * properly handle 64-bit data because the value gets down cast to a long.
79 * The "put_user" functions already handle 64-bit data properly but we add
80 * "user64" versions for completeness
81 */
82 #define get_user(x,ptr) \
83 __get_user_check((x),(ptr),sizeof(*(ptr)))
84 #define get_user64(x,ptr) \
85 __get_user64_check((x),(ptr),sizeof(*(ptr)))
86 #define put_user(x,ptr) \
87 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
88 #define put_user64(x,ptr) put_user(x,ptr)
89
90 #define __get_user(x,ptr) \
91 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
92 #define __get_user64(x,ptr) \
93 __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
94 #define __put_user(x,ptr) \
95 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
96 #define __put_user64(x,ptr) __put_user(x,ptr)
97
98 extern long __put_user_bad(void);
99
100 #define __put_user_nocheck(x,ptr,size) \
101 ({ \
102 long __pu_err; \
103 __chk_user_ptr(ptr); \
104 __put_user_size((x),(ptr),(size),__pu_err); \
105 __pu_err; \
106 })
107
108 #define __put_user_check(x,ptr,size) \
109 ({ \
110 long __pu_err = -EFAULT; \
111 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
112 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
113 __put_user_size((x),__pu_addr,(size),__pu_err); \
114 __pu_err; \
115 })
116
117 #define __put_user_size(x,ptr,size,retval) \
118 do { \
119 retval = 0; \
120 switch (size) { \
121 case 1: \
122 __put_user_asm(x, ptr, retval, "stb"); \
123 break; \
124 case 2: \
125 __put_user_asm(x, ptr, retval, "sth"); \
126 break; \
127 case 4: \
128 __put_user_asm(x, ptr, retval, "stw"); \
129 break; \
130 case 8: \
131 __put_user_asm2(x, ptr, retval); \
132 break; \
133 default: \
134 __put_user_bad(); \
135 } \
136 } while (0)
137
138 /*
139 * We don't tell gcc that we are accessing memory, but this is OK
140 * because we do not write to any memory gcc knows about, so there
141 * are no aliasing issues.
142 */
143 #define __put_user_asm(x, addr, err, op) \
144 __asm__ __volatile__( \
145 "1: "op" %1,0(%2)\n" \
146 "2:\n" \
147 ".section .fixup,\"ax\"\n" \
148 "3: li %0,%3\n" \
149 " b 2b\n" \
150 ".previous\n" \
151 ".section __ex_table,\"a\"\n" \
152 " .align 2\n" \
153 " .long 1b,3b\n" \
154 ".previous" \
155 : "=r" (err) \
156 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
157
158 #define __put_user_asm2(x, addr, err) \
159 __asm__ __volatile__( \
160 "1: stw %1,0(%2)\n" \
161 "2: stw %1+1,4(%2)\n" \
162 "3:\n" \
163 ".section .fixup,\"ax\"\n" \
164 "4: li %0,%3\n" \
165 " b 3b\n" \
166 ".previous\n" \
167 ".section __ex_table,\"a\"\n" \
168 " .align 2\n" \
169 " .long 1b,4b\n" \
170 " .long 2b,4b\n" \
171 ".previous" \
172 : "=r" (err) \
173 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
174
175 #define __get_user_nocheck(x, ptr, size) \
176 ({ \
177 long __gu_err; \
178 unsigned long __gu_val; \
179 __chk_user_ptr(ptr); \
180 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
181 (x) = (__typeof__(*(ptr)))__gu_val; \
182 __gu_err; \
183 })
184
185 #define __get_user64_nocheck(x, ptr, size) \
186 ({ \
187 long __gu_err; \
188 long long __gu_val; \
189 __chk_user_ptr(ptr); \
190 __get_user_size64(__gu_val, (ptr), (size), __gu_err); \
191 (x) = (__typeof__(*(ptr)))__gu_val; \
192 __gu_err; \
193 })
194
195 #define __get_user_check(x, ptr, size) \
196 ({ \
197 long __gu_err = -EFAULT; \
198 unsigned long __gu_val = 0; \
199 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
200 if (access_ok(VERIFY_READ, __gu_addr, (size))) \
201 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
202 (x) = (__typeof__(*(ptr)))__gu_val; \
203 __gu_err; \
204 })
205
206 #define __get_user64_check(x, ptr, size) \
207 ({ \
208 long __gu_err = -EFAULT; \
209 long long __gu_val = 0; \
210 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
211 if (access_ok(VERIFY_READ, __gu_addr, (size))) \
212 __get_user_size64(__gu_val, __gu_addr, (size), __gu_err); \
213 (x) = (__typeof__(*(ptr)))__gu_val; \
214 __gu_err; \
215 })
216
217 extern long __get_user_bad(void);
218
219 #define __get_user_size(x, ptr, size, retval) \
220 do { \
221 retval = 0; \
222 switch (size) { \
223 case 1: \
224 __get_user_asm(x, ptr, retval, "lbz"); \
225 break; \
226 case 2: \
227 __get_user_asm(x, ptr, retval, "lhz"); \
228 break; \
229 case 4: \
230 __get_user_asm(x, ptr, retval, "lwz"); \
231 break; \
232 default: \
233 x = __get_user_bad(); \
234 } \
235 } while (0)
236
237 #define __get_user_size64(x, ptr, size, retval) \
238 do { \
239 retval = 0; \
240 switch (size) { \
241 case 1: \
242 __get_user_asm(x, ptr, retval, "lbz"); \
243 break; \
244 case 2: \
245 __get_user_asm(x, ptr, retval, "lhz"); \
246 break; \
247 case 4: \
248 __get_user_asm(x, ptr, retval, "lwz"); \
249 break; \
250 case 8: \
251 __get_user_asm2(x, ptr, retval); \
252 break; \
253 default: \
254 x = __get_user_bad(); \
255 } \
256 } while (0)
257
258 #define __get_user_asm(x, addr, err, op) \
259 __asm__ __volatile__( \
260 "1: "op" %1,0(%2)\n" \
261 "2:\n" \
262 ".section .fixup,\"ax\"\n" \
263 "3: li %0,%3\n" \
264 " li %1,0\n" \
265 " b 2b\n" \
266 ".previous\n" \
267 ".section __ex_table,\"a\"\n" \
268 " .align 2\n" \
269 " .long 1b,3b\n" \
270 ".previous" \
271 : "=r"(err), "=r"(x) \
272 : "b"(addr), "i"(-EFAULT), "0"(err))
273
274 #define __get_user_asm2(x, addr, err) \
275 __asm__ __volatile__( \
276 "1: lwz %1,0(%2)\n" \
277 "2: lwz %1+1,4(%2)\n" \
278 "3:\n" \
279 ".section .fixup,\"ax\"\n" \
280 "4: li %0,%3\n" \
281 " li %1,0\n" \
282 " li %1+1,0\n" \
283 " b 3b\n" \
284 ".previous\n" \
285 ".section __ex_table,\"a\"\n" \
286 " .align 2\n" \
287 " .long 1b,4b\n" \
288 " .long 2b,4b\n" \
289 ".previous" \
290 : "=r"(err), "=&r"(x) \
291 : "b"(addr), "i"(-EFAULT), "0"(err))
292
293 /* more complex routines */
294
295 extern int __copy_tofrom_user(void __user *to, const void __user *from,
296 unsigned long size);
297
298 extern inline unsigned long
299 copy_from_user(void *to, const void __user *from, unsigned long n)
300 {
301 unsigned long over;
302
303 if (access_ok(VERIFY_READ, from, n))
304 return __copy_tofrom_user((__force void __user *)to, from, n);
305 if ((unsigned long)from < TASK_SIZE) {
306 over = (unsigned long)from + n - TASK_SIZE;
307 return __copy_tofrom_user((__force void __user *)to, from, n - over) + over;
308 }
309 return n;
310 }
311
312 extern inline unsigned long
313 copy_to_user(void __user *to, const void *from, unsigned long n)
314 {
315 unsigned long over;
316
317 if (access_ok(VERIFY_WRITE, to, n))
318 return __copy_tofrom_user(to, (__force void __user *) from, n);
319 if ((unsigned long)to < TASK_SIZE) {
320 over = (unsigned long)to + n - TASK_SIZE;
321 return __copy_tofrom_user(to, (__force void __user *) from, n - over) + over;
322 }
323 return n;
324 }
325
326 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long size)
327 {
328 return __copy_tofrom_user((__force void __user *)to, from, size);
329 }
330
331 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long size)
332 {
333 return __copy_tofrom_user(to, (__force void __user *)from, size);
334 }
335
336 #define __copy_to_user_inatomic __copy_to_user
337 #define __copy_from_user_inatomic __copy_from_user
338
339 extern unsigned long __clear_user(void __user *addr, unsigned long size);
340
341 extern inline unsigned long
342 clear_user(void __user *addr, unsigned long size)
343 {
344 if (access_ok(VERIFY_WRITE, addr, size))
345 return __clear_user(addr, size);
346 if ((unsigned long)addr < TASK_SIZE) {
347 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
348 return __clear_user(addr, size - over) + over;
349 }
350 return size;
351 }
352
353 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
354
355 extern inline long
356 strncpy_from_user(char *dst, const char __user *src, long count)
357 {
358 if (access_ok(VERIFY_READ, src, 1))
359 return __strncpy_from_user(dst, src, count);
360 return -EFAULT;
361 }
362
363 /*
364 * Return the size of a string (including the ending 0)
365 *
366 * Return 0 for error
367 */
368
369 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
370
371 /*
372 * Returns the length of the string at str (including the null byte),
373 * or 0 if we hit a page we can't access,
374 * or something > len if we didn't find a null byte.
375 *
376 * The `top' parameter to __strnlen_user is to make sure that
377 * we can never overflow from the user area into kernel space.
378 */
379 extern __inline__ int strnlen_user(const char __user *str, long len)
380 {
381 unsigned long top = current->thread.fs.seg;
382
383 if ((unsigned long)str > top)
384 return 0;
385 return __strnlen_user(str, len, top);
386 }
387
388 #define strlen_user(str) strnlen_user((str), 0x7ffffffe)
389
390 #endif /* __ASSEMBLY__ */
391
392 #endif /* _PPC_UACCESS_H */
393 #endif /* __KERNEL__ */
kernel-based virtual machine